Australian researchers have discovered a gene linked to the most common form of epilepsy, which could pave the way for genetic testing.

The study, conducted by the Florey Institute of Neuroscience and Mental Health, has found a gene which causes focal epilepsy and can be passed down through families.

Lead researcher, Professor Ingrid Scheffer, says the discovery is significant.

"This discovery is paradigm shifting," Prof Scheffer said.

"It means that if you have focal epilepsy and there is no cause known, then this gene should be tested to look for a mutation."

Previously, it was believed focal epilepsy was caused by brain injury or tumours.

Sufferers of focal epilepsy, a sub-type of epilepsy also known as partial epilepsy, experience a localised disturbance in cerebral function before seizures, which can cause twitching, hallucinations or other impairments in cognitive function.